What is wheel backspace?

Chris

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This question comes up from time to time, so I figured I'd make a thread about it.

This illustration pretty much says it all:

wheel-backspace-diagram.jpg


So for instance, if you had a wheel with 3" backspace and a wheel with 4" backspace, the 3" backspace wheel would move outwards more, whereas the 4" backspace wheel would move inwards more.

Hopefully this makes it easy to understand for beginners.
 
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So how do I know how much back space I need before I order rims ?

That’s based off of what tire size you plan on running, what size wheel, what kind of fender flares you have, and how much (if any) you want your tire to stick out past your fender flare.
 
Clear as mud.

I am looking at BFG Mud Terrain 33 x 12.5 tires. For some reason when I look up rims for them < on a 06 TJ > I get different bolt patterns as well as different back spacing.
dc97403d0a514272032f2d5a9c015cc5--mud-jeep-jk.jpg
pro_comp_steel_wheel_252_series.jpg

Technical Details
  • Wheel Size: 15x10
  • Bolt Pattern: 5 on 5.5
  • Backspace: 3.75
  • Max Load: 1800
  • Offset: -44
  • Finish: Flat Black
  • Center Caps and Lug Nuts Not Included
  • Replacement Center Cap Part Number: PXA1425017
 
For that setup 3.75” backspacing will work great!

However, the correct lug pattern for a TJ is 5 x 4.5.
 
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Often overlooked is why BS between two rims will be very different yet the tire is still in the same place relative to the center of the rim or offset. That's because the BS dimension doesn't tell the whole story. Some rims have a very pronounced lip that points away from the WMS and is outside the tire bead by a fair bit. Other rims have a very small flat lip that holds the tire bead and both affect BS in different ways but the tire has the same offset to the WMS.

You need to also know the offset and rim width when you compare back spacing dimensions.
 
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Hello, I had a quick question about the wheels and tires I am thinking about putting on my jeep. It is a 2006 Jeep Wrangler TJ.

I am putting a 3 inch suspension lift on it and am going to put 33x12.5R15s on it.
The following is some details on the wheels and tires.
  • Bolt Pattern: 5 on 4.5
  • Backspace: 3.75
  • 33x12.5R15, Pro Comp Xtreme MT2 Tires.
I know my question is very similar to Randy's but I am new to this and am trying to make sure I do the right things to the Jeep.
Thanks in advance for any answers guys!
 
Hello, I had a quick question about the wheels and tires I am thinking about putting on my jeep. It is a 2006 Jeep Wrangler TJ.

I am putting a 3 inch suspension lift on it and am going to put 33x12.5R15s on it.
The following is some details on the wheels and tires.
  • Bolt Pattern: 5 on 4.5
  • Backspace: 3.75
  • 33x12.5R15, Pro Comp Xtreme MT2 Tires.
I know my question is very similar to Randy's but I am new to this and am trying to make sure I do the right things to the Jeep.
Thanks in advance for any answers guys!

What size are the wheels, 15x8 or 15x10? 15x8 I hope?